/Engine/Source/Runtime/Engine/Public/WorldPartition/HLOD/HLODBuilder.h
Should return true if components generated from this builder need a warmup phase before being made visible. If your components are using virtual textures or Nanite meshes, this should return true, as it will be necessary to warmup the VT & Nanite caches before transitionning to HLOD. Otherwise, it's likely the initial first frames could show a low resolution texture or mesh.
virtual bool RequiresWarmup() const